This invention relates to belt drives, and more particularly to techniques for tracking the belt.
Endless belt drives find utility in number of different applications. One exemplary application is that of paper/media handling systems, e.g. in an inkjet printer. The belt drive can be used to move the print media along a media path for inkjet printing in an exemplary application. The belt is positioned over rollers and platen surfaces. There is a need to track the lateral position of the belt in order to properly control it for good image quality, and to prevent damage to the belt and other machine components in the event of a malfunction. The belt needs to be controlled from running off the rollers and becoming damaged.
In accordance with one aspect of the invention, a belt tracking system is described for an endless belt mounted on a roller system, the belt driven in a first direction by a belt drive system. The tracking system includes a set of periodic belt indicia formed on the belt along one or more axes aligned with the first direction. A sensor system tracks movement of the belt in a lateral direction transverse to the first direction and senses the set of belt indicia to provide sensor system signals. An actuator system effects movement of the belt in the lateral direction, the actuator system responsive to the sensor system signals for nominally maintaining a position of the belt relative to the transverse direction. A controller is responsive to the sensor system signals for detecting that the belt has tracked outside an allowable belt movement range and taking protective actions to prevent the belt from damage due to undesired lateral tracking movement.